Candida albicans is one of the most frequently isolated fungal pathogens of humans. It can undergo reversible morphogenetic transitions among budding yeast, pseudohyphal, and hyphal growth forms. Its unique ability to switch from yeast to hyphal growth in response to various environmental signals not only is inherent to its pathogenicity, but also provides an excellent paradigm to understand how signaling pathways coordinate growth and development. The objectives of this research are to understand how hyphal signaling pathways integrate external signals with temporal and spatial cues to generate linear hyphal filaments. There are five specific aims: (1) Activation of hyphal signaling during the initial response to hyphal inducing conditions. (2) Regulation of hyphal signaling by cell cycle. (3) Regulation of hyphal signaling by cell polarity. (4) Identification of targets of hyphal signaling that control cell polarity. (5) Apical cell-specific localization and linear cell division. [unreadable] [unreadable] [unreadable]